maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[DAGCombine] Use FoldConstantArithmetic() to perform C2-(A+C1) -> (C2-C1)-A fold 

Summary:
No tests change, and i'm not sure how to test this, but it's better safe than sorry.

Reviewers: spatel, RKSimon, craig.topper, t.p.northover

Reviewed By: craig.topper

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62663

llvm-svn: 362132
This commit is contained in:
Roman Lebedev 2019-05-30 19:27:26 +00:00
parent cc9a9cf237
commit 9ff3159b4a
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -2868,7 +2868,9 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
SDValue N11 = N1.getOperand(1);
if (isConstantOrConstantVector(N0, /* NoOpaques */ true) &&
isConstantOrConstantVector(N11, /* NoOpaques */ true)) {
SDValue NewC = DAG.getNode(ISD::SUB, DL, VT, N0, N11);
SDValue NewC = DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, N0.getNode(),
N11.getNode());
assert(NewC && "Constant folding failed");
return DAG.getNode(ISD::SUB, DL, VT, NewC, N1.getOperand(0));
}
}